Secret recording in Brazil puts Senate leader on defensive

Brazil's acting President Michel Temer, left, talks with President of the National Congress Sen. Renan Calheiros, during meeting to deliver to Congress the revision project of the government's fiscal target, in Brasilia, Brazil, Monday, May 23, 2016. Brazil's interim government is under fire after a recording emerged of the planning minister discussing a purported pact to push for President Dilma Rousseff's impeachment to stall a massive corruption probe. (AP Photo/Eraldo Peres)
(The Associated Press)

Brazil' acting President Michel Temer, right, listens to former President Jose Sarney during the swearing-in ceremony of the new Culture Minister Marcelo Calero at Planalto presidential palace in Brasilia, Brazil, Tuesday, May 24, 2016. Temer recreated the ministry after closing it, following intense protest by Brazilian artists. Temer took over after President Dilma Rousseff was impeached earlier this month for allegedly using accounting tricks in managing the federal budget. (AP Photo/Eraldo Peres)
(The Associated Press)

Brazil' acting President Michel Temer speaks during the swearing-in ceremony of his new Culture Minister Marcelo Calero at Planalto presidential palace in Brasilia, Brazil, Tuesday, May 24, 2016. Temer recreated the ministry after closing it, following intense protest by Brazilian artists. Temer took over after President Dilma Rousseff was impeached earlier this month for allegedly using accounting tricks in managing the federal budget. (AP Photo/Eraldo Peres)
(The Associated Press)

RIO DE JANEIRO – A secretly recorded conversation shows the head of Brazil's Senate proposing to weaken one of the key tools prosecutors have used to trap politicians and businessmen in a sweeping corruption scandal.

The transcript published Wednesday by the Folha de S. Paulo newspaper adds to widespread suspicions that top politicians are trying to stifle investigations against them.

The transcript shows Senate president Renan Calheiros suggesting to change laws so that nobody can make a plea bargain after being arrested.

Prosecutors have used such offers of lighter sentences to convince suspects to implicate high-ranking politicians and businessmen in billions of dollars of alleged bribes centered on the government's Petrobras oil company.

Calheiros' office issued a statement acknowledging the conversation but insisting he wasn't trying to tamper with the Petrobras probe.